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Öğe Anoxybacillus sp. SO B1 immobilized Amberlite XAD-16 for solid phase preconcentration of Cu(II), Pb(II) and their determinations by flame atomic absorption spectrometry(Bioremediation Journal, 2016) Varhan, Elif; Özdemir, Sadin; Dolak, İbrahim; Okumuş, Veysi; Dündar, Abdurrahman; Ziyadanoğulları, Berrin; Aksoy, Zehra; Onat, RukenA new method for the determination of Cu(II) and Pb(II) by flame atomic absorption spectrometry (FAAS) after preconcentrating on a column containing Anoxybacillus sp. SO B1–immobilized Amberlite XAD-16 was developed. The functional groups of Anoxybacillus sp. SO B1 immobilized on Amberlite XAD-16 were characterized in KBr tablets by Fourier transform infrared (FT-IR) spectrometry. Various parameters such as pH, amount of the adsorbent, eluent type and volume, and flow rate of the sample solution were studied. The optimum pH values of quantitative sorption for Cu(II) and Pb(II) were found to be pH 7.0 and 5.0 and Cu(II) and Pb(II) ions could be quantitatively eluted with 5.0 ml of 1.0 mol L¡1 HCI and 10.0 ml of 0.25 mol L¡1 HNO3, respectively. Recoveries of Cu(II) and Pb(II) were found to be 100.9 § 1.57% and 100.3 § 0.49% (N D 5), the limits of detection of Cu(II) and Pb(II) in the determination by FAAS (3 s, N D 10) were found to be 0.8 and 1.6 mg L¡1, respectively. The proposed enrichment method was applied for metal ion determination from water samples such as two parts of Tigris River water in Diyarbakır and Elazı_g, Lake of Hazar in Elazı_g, and tap water in Diyarbakır. Furthermore, the accuracy of the proposed method was verified by studying the analytical recovery and by analyzing certified reference material (NCS-DC 73350 leaves of poplar).Öğe Antioxidant properties of cultured mycelia from four pleurotus species produced in submerged medium.(International Journal of Food Properties, 2013) Dündar, Abdurrahman; Okumuş, Veysi; Özdemir, Sadin; Yıldız, AbdulnasırThe ethanolic extracts of dried cultured mycelia of Pleurotus ostreatus, Pleurotus eryngii, Pleurotus florida, and Pleurotus sajor-caju were analyzed for antioxidant activity in different systems. Tests used are as follows: reducing power, free radical scavenging, superoxide anion radical scavenging, total antioxidant activity, metal chelating activitiy, etc.; total phenolic content was determined. The percentage inhibition of P. ostreatus, P. eryngii, P. florida, and P. sajor-caju at 20 mg/mL concentration on peroxidation in a β-carotene–linoleic acid system was 57.19, 60.68, 62.12, and 58.81%, respectively. The reducing power of P. eryngii was higher than the other samples, and its value was 0.86 at 10 mg/mL concentration. P. ostreatus and P. sajor-caju proved to be better at scavenging superoxide anion radicals than the P. eryngii and P. florida. In the scavenging effect of DPPH radical test, P. ostreatus showed the highest activity potential and P. sajor-caju showed the strongest metal chelating capacity.Öğe Antioxidant properties, chemical composition and nutritional value of terfezia boudieri (Chatin) from Turkey.(Food Science and Technology International, 2012) Dündar, Abdurrahman; Yeşil, Ömer Faruk; Acay, Hilal; Okumuş, Veysi; Özdemir, Sadin; Yıldız, AbdulnasırOur objectives were to investigate the chemical composition, nutritive value and antioxidant activity potentials of Terfezia boudieri Chatin collected from different areas from Southeast of Turkey. The amounts of energy, protein, fat, carbohydrate, crude fibre, moisture and ash were 34.00–65.00 (kcal/100 g), 1.40–2.73, 0.86–1.71, 4.84–11.60, 80.86–90.33 (g/100 g, f.w.) and 1.02–1.98 g/100 g dry mass, respectively. Fatty acids and amino acids analyses revealed that linoleic acid and glutamic acid were, respectively the most abundant. Among the essential amino acids leucine was the highest amount and this was followed by threonine. Magnesium was the most abundant element with a concentration value of 182.30 mg/100 g dry mass. T. boudieri exhibited excellent antioxidant activity when compared with standard compounds. In total antioxidant and chelating effect on ferrous ions activity T. boudieri showed the highest activity against the standards. Additionally, at all studied tests antioxidant activity of the mushroom increased with increasing concentration. The total phenolic content of T. boudieri was found as 8.45 mg/g.Öğe Biosorption of 2,4-D, 2,4-DP and 2,4-DB from aqueous solution by using thermophilic anoxybacillus flavitermus and analysis by high performance thin layer chromatography: equilibrium and kinetic studies(Environmental Progress & Sustainable Energy, 2012) Özdemir, Sadin; Matpan, Fatma; Okumuş, Veysi; Dündar, Abdurrahman; Kılınç, ErsinIn this study, the potential biosorption characteristics of the thermophilic Anoxybacillus flavithermus (A. flavithermus) was investigated for the removal of the chlorophenoxy acid derivates, namely, 2,4-dichlorophenoxy acetic acid (2,4-D), 2,4-dichlorophenoxy propanoic acid (2,4-DP or dichlorprop), and 2,4-dichlorophenoxy butyric acid (2,4-DB). The experiments were performed for the simultaneous biosorption of the studied pesticides. Optimum biosorption conditions were determined as a function of contact time, pH of the solution, amount of biomass, and initial pesticides concentrations. The concentrations of the pesticides in the remaining solutions were simultaneously analyzed by high performance thin layer chromatography. The optimum parameters were found as pH: 4.0 for biosorption medium, 60 min of contact time, 50 mg of bacteria, and 50 mg L21 of initial pesticides concentrations. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the pesticides by A. flavithermus as biomass. Biosorption of pesticides on to A. flavithermus showed pseudo first-order rate kinetics at different initial concentration of pesticides and different temperatures. The experimental adsorption data were fitted both the Langmuir and Freundlich adsorption models. Fourier-transform Infrared spectroscopy was used to understand the bonding mechanism of pesticides to biosorbent and surface functionality of the biosorbent The highest pesticide uptake was calculated from Langmuir isotherm and found to be 24.15 mg/g for 2,4-D Among the studied pesticides, 2,4-DP showed difference adsorption behavior. According to in your comments the reason of this that 2,4-DP contain an asymmetric carbon atom, which provide a molecular chirality.Öğe Biosorption of chlorophenoxy acid herbicides from aqueous solution by using low-cost agricultural wastes.(Desalination and Water Treatment, 2015) Okumuş, Veysi; Çelik, Kadir; Özdemir, Sadin; Dündar, Abdurrahman; Kılınç, ErsinThe potential biosorption abilities of apple shell (AS), orange peel (OP), banana peel (BP), and millet waste (MW) as a bio-waste material to remove 2,4-dichlorophenoxy acetic acid (2,4-D), 2,4-dichlorophenoxy propanoic acid (2,4-DP), and 2,4-dichlorophenoxy butyric acid (2,4-DB) from aqueous solution were investigated in batch condition. Optimum biosorption conditions were determined as a function of contact time, pH of the solution, amount of biomass, and initial pesticide concentrations. The concentrations of the pesticides in the remaining solutions were simultaneously determined by high performance thin layer chromatography. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the pesticides by agricultural wastes. The experimental adsorption data were fitted to Langmuir adsorption models (r2 > 0.99). It was found that adsorption of 2,4-DP was higher for all biosorbent. The highest maximum adsorption capacities of 2,4-DP were found as 40.08, 22.71, 33.26, and 45.45 mg/g, respectively, for AS, OP, BP, and MW. Maximum adsorption capacity was obtained for 2,4-D as OP >MW> BP > AS, 2,4-DP as MW> AS > BP > OP, and 2,4-DB as OP > AS > BP > MW. From the results, it can be said that MW was an effective biosorbent for removal of 2,4-DP and OP was an effective biosorbent for removal of 2,4-D and 2,4-DB through the studied pesticides. Optimum biosorption conditions were determined as 60 min of contact time, 100 mg of biomass, AS at pH 6.0, OP at pH 6.0, MW at pH 7.0, and BP at pH 7.0. FT-IR was employed to understand the surface properties of biosorbents. According to the results, agricultural wastes have high adsorption capacity.Öğe Design of novel binuclear phthalocyanines formed by dioxyphenyl bridges: Synthesis and investigation of thermal and antioxidant properties(Zeitschrift für anorganische und allgemeine Chemie., 2012) Ağırtaş, Salih; Gümüş, İlkay; Okumuş, Veysi; Dündar, Abdurrahman4,4_-(1,4-Phenylenebis(oxy)diphthalonitrile was synthesized by reaction of hydroquinone with 4-nitrophthalonitrile. Binuclear metallophthalocyanines 2–4 were obtained by the reaction between 4,4_-(1,4-phenylenebis(oxy)diphthalonitrile and 4-(benzo [d] [1,3] dioxol- 5-ylmethoxy)phthalonitrile in the presence of metal salts. These new compounds were characterized by using elemental analysis, FTIR, 1H-NMR and UV/Vis spectroscopic data. Thermal properties of phthalocyanines 2-4 were investigated by TG and DTA. In addition, antioxidant properties of compounds II, 3 and 4 were investigated. Their radical-scavenging capacity and chelating effects was fully studied. The maximum 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) were obtained from compound 3. Chelating effects on ferrous ions were 91.6 % at concentration of 100 mgL–1 with compound II.Öğe DNA cleavage properties and synthesis of metallophthalocyanines with 5-methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-oxy substituents.(Inorganic and Nano-Metal Chemistry, 2017) Ağırtaş, Salih; Öndeş, Yusuf; Özdemir, Sadin; Okumuş, VeysiThe aim of the present study is to perform synthesis of novel metallophthalocyanines (pcs) with high solubility. The synthesis and characterization of 5-methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-yloxysubstituted zinc, magnesium, and cobalt pcs are reported. These compounds have been characterized using electronic absorption, nuclear magnetic resonance spectroscopy, infrared, elemental analysis and mass spectra. The aggregation investigations carried out in different concentrations indicate that 5- methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-yloxy-substituted pc complexes do not have any aggregation behavior for the concentration range of 1 £ 10¡5¡1 £ 10¡6 M in THF. DPPH radical scavenging activity, metal chelating activity, and reducing power of the compounds were evaluated. The DNA gel electrophoresis studies revealed that new phthalonitrile and its metallophthalocyanine compounds cleavaged plasmid DNA (pBR322). Additionally, the ground-state geometries of the complexes were optimized using density functional theory methods at B3LYP/6-31G (d, p) level in order to obtain information about the 3D geometries and electronic structure.Öğe Heavy metals biosorption by submerged aquatic plant nasturtium officinale(Asian Journal of Chemistry, 2010) Okumuş, Veysi; Başaran, Davut; Onay, AhmetIn the present investigation an aquatic plant, Nasturtium officinale was examined for its biosorption ability of heavy metal ions. The results obtained from biosorption experiments were used to understand the driving forces that govern the interaction between metal ions and biosorbent. The experimental biosorption data were fitted to the Scatchard plot, Langmiur and Freundlich isotherms. According to the parameters of the Langmiur isotherm, the maximum biosorption capacities of Cd2+ and Co2+ were 0.56 and 0.49 mg/g, respectively. In view of Freundlich isotherms, the maximum biosorption capacities of Cd2+ and Co2+ were 2.23 mg/g for both of metal ions.Öğe İmmobilize Coriolus versicolor kullanılarak Pb (II) iyonlarının biyosorpsiyonu ve önderiştirilmesi(İKSAD ULUSLARARASI YAYINEVİ, 2018) Okumuş, Veysi; Akcan, Nurullah; Canpolat, GurbetAğır metaller gıda sektörünün başlıca kirleticileri arasında yer alır ve özellikle bizim gibi gelişmekte olan ülkelerde en önemli sorunlardan biri olarak düşünülebilir. Gıdalardaki ağır metallerin aşırı içeriği, özellikle kardiyovasküler, böbrek, sinir ve diğer hastalıklarla birlikte bir dizi hastalığın etiyolojisi ile ilişkilidir. Kurşun, ciddi bir kümülatif vücut zehiridir ve vücut sistemimize hava, su ve yiyecek yoluyla girer. Bazı ülkelerde insanlar, içme suyunun kurşun borulardan kaynaklanan kirlenmeleri nedeniyle önemli ölçüde bu metale maruz kalabilir. Kurşun kirliliğinin çoğu kümülatif etki gösterir ve insanlar kurşun ile uzun süre teması sonucunda, küçük konsantrasyonlarda bile sağlığa zararlı olabilir. Gıda ve su örneklerinde kurşun gibi metal iyonlarının aletli analizle doğrudan belirlenmesi, düşük miktarda olmaları nedeniyle çoğu zaman zordur. Bu nedenle, kantitatif olarak belirlenmeden önce genellikle bir ayırma ve önderiştirme tekniği gereklidir. Bu çalışmada Katı faz ekstraksiyonu (SPE) yöntemi ile Pb iyonlarının önderiştirilmesi için alternatif bir yöntem geliştirilmiştir., Pb'nin indüktif eşleşmiş plazma optik emisyon spektrometrisi (ICP-OES) ile belirlenmesinden önce önderiştirilmesi için immobilize Coriolus versicolor fungal biyosorbent olarak kullanıldı. Geliştirilen SPE yöntemindeki bazı parametreler (pH, akış hızı, biyosorbent miktarı, kolonun tekrar kullanılabilirliği) optimize edildi. Yöntemin doğruluğu sertifikalı referans çay numunelerinin analizi ile doğrulandı. Geliştirilen kolonun 30 kullanımdan sonra bile oldukça stabil olduğu belirlendi.Öğe In vitro propagation of Diyarbakır watermelons and comparison of direct seeded and transplanted watermelon(Turkish Journal of Biology, 2011) Okumuş, Veysi; Pirinç, Vedat; Onay, Ahmet; Başaran, DavutA rapid protocol using shoot tip explants for micropropagation of Diyarbakır watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] types Surme, Beyazkış and Karakış was achieved. Shoot tips from 5-day-old in vitro germinated seedlings were cultured on shoot regeneration medium for 3 weeks. Th e eff ects of the diff erent concentrations of benzyl adenine (BA) and carbohydrate types on shoot proliferation were examined. Th e results confi rmed that a range of 0.5-1.0 mg/L of BA was almost equally eff ective in promoting the shoot length of cultures in the 3 genotypes. Sucrose, in the presence of BA, was superior to other carbohydrates for the 3 genotypes studied in terms of the number of proliferated shoots and the average shoot length obtained. Th e highest percentage of rooting was achieved when medium supplemented with 1.0 mg/L of indole-3-butyric acid (IBA) was used for the 3 genotypes. Th e highest frequency of acclimatized plantlets for the 3 genotypes was 85%, 85%, and 90%, respectively, in sterile compost, when the shoots of Beyazkış, Karakış, and Surme were rooted in the IBA-supplemented rooting treatments. Th e Surme genotype produced a signifi cantly higher yield and mean fruit weight than the Beyazkış and Karakış genotypes in both direct-seeded and transplanted watermelons. Th e main soluble sugar of the experimental types was separated, identifi ed, and quantifi ed using high performance liquid chromatography (HPLC). Fructose was found to be the most abundant sugar and was highly detected in Beyazkış for the seeded watermelon and in Karakış for the transplanted watermelon. Th is demonstrates that in vitro propagation can be used to produce high quality diploid Diyarbakır watermelon for use in breeding lines.Öğe In vitro propagation of Diyarbakır watermelons and comparison of direct-seeded and transplanted watermelon(2011) Okumuş, Veysi; Pirinç, Vedat; Onay, Ahmet; Başaran, DavutSürgün ucu eksplantları kullanılarak Diyarbakır karpuz tipleri Sürme, Beyazkış ve Karakış’ın mikroçoğaltımı için hızlı bir protokol geliştirilmiştir. İn vitro koşullarda çimlendirilmiş 5 günlük fi delerin sürgün uçları 3 haft a süreyle sürgün rejenerasyon ortamında kültüre alınmıştır. Farklı konsantrasyonlardaki benzil adenin (BA) ve karbonhidrat tiplerinin sürgün proliferasyonuna etkileri test edilmiştir. Sonuçlar her 3 genotipte de 0,5-1,0 mg/L aralığındaki BA ortamında sürgün uzunluklarının hemen hemen eşit olduğunu göstermiş ve BA ortamına sukroz eklenmesiyle ortalama sürgün sayısı ve sürgün uzunluğunun diğer karbonhidratlara göre daha yüksek olduğu tespit edilmiştir. Her 3 genotip için en iyi köklenme ortamının 1.0 mg/L IBA olduğu belirlenmiş ve IBA’da köklendirilen sürgünler Beyazkış ve Karakış için % 85, Sürme için % 90 başarıyla steril komposta aktarılmıştır. Sürme genotipinde hem doğrudan tohumdan hem de aktarılmış fi delerden elde edilen ürün verimi ve ortalama meyve ağırlığı, Beyazkış ve Karakış’tan daha yüksek bulunmuştur. Temel çözünür şekerler HPLC (yüksek performanslı sıvı kromatografi ) ile kantitatif olarak tespit edilmiştir. Beyazkış’ta tohumdan elde edilen ve Karakış’ta aktarılmış fideden elde edilen karpuzda, en çok bulunan şeker fruktoz olarak tespit edilmiştir. Bu sonuçlarla yüksek kaliteli Diyarbakır karpuzunun in vitro çoğaltılabileceği gösterilmiştir.Öğe Isolation a thermophilic anoxybacillus flavithermus sp. nov. and production of thermostable α-amylase under solid-state fermentation (SSF)(Annals of Microbiology, 2012) Özdemir, Sadin; Matpan, Fatma; Okumuş, Veysi; Dündar, Abdurrahman; Ulutaş, Sefa; Kumru, MertA new bacteria was isolated from hot-spring water of Gazlıgöl, Afyonkarahisar in Turkey. Based on morphological and biochemical tests and 16S rRNA gene sequence analysis, the isolate belonged to the Anoxybacillus flavithermus species which has 99% similarity with the bacterium DNA. The production of α-amylase by thermophilic Anoxybacillus flavithermus was investigated under solid-state fermentation by using some agricultural waste as substrates. Solid substrates such as rice husk, banana husk, millet, water melon husk, lentil bran, wheat bran and maize oil cake were studied for enzyme production. Of these, rice husk was proved as the best substrate for α-amylase production (1,271 U/mg). The maximum α-amylase production was observed as 1,803 U/mg at 72 h, 1,000 μm particle size, 70% initial moisture content (w/v), and 40% inoculum level (v/w). Among the various nitrogen sources tested, 1% peptone (3,170 U/mg) was found to be the best nitrogen source for α-amylase production. As additional carbon sources, 1% starch (2,364 U/mg) enhanced α-amylase production. The optimum temperature for the activity of α-amylase was found to be 70°C. The enzyme was optimally active at pH 6.0 and stable in the pH range of 6.0–8.0.Öğe Metallo phthalocyanines bearing (2-((2-hydroxyethyl) (p-tolyl)amino)ethoxy) and (2-((2-phenoxyethyl) (p-tolyl)amino)ethoxy) phthalonitrile substituents: Synthesis, characterization, aggregation behavior, antioxidant and antibacterial activity(Synthetic Metals, 2014) Çelebi, Metin; Ağırtaş, Salih; Özdemir, Sadin; Okumuş, VeysitThe novel phthalonitrile derivatives bearing (2-((2-hydroxyethyl)(p-tolyl)amino)ethoxy) and (2-((2-phenoxyethyl)(p-tolyl)amino)ethoxy)phthalonitrile substituents at peripheral position were preparedby a nucleophilic displacement reaction. Cyclotetramerization of these phthalonitrile derivatives in thepresence of corresponding metal salts gave the new metallophthalocyanines. The novel compounds werecharacterized by using various spectroscopic data. The aggregation investigations carried out in differ-ent concentrations indicate that phthalocyanine compounds do not have any aggregation behavior forthe concentration range of 10−4–10−6M in tetrahydrofuran. In vitro three antioxidant test methods,namely diphenylpicrylhydrazyl radical scavenging activity, metal chelating activity and reducing powerwere used to determine the antioxidant activity of compounds. Compounds were analyzed for theirantibacterial activity against some bacteria by using the disk-diffusion method.Öğe Metallo phthalocyanines bearing 2-Isopropyl-6-methylpyrimidin-4-yloxy substituents: synthesis, characterization, aggregation behavior, antioxidant and antibacterial activity, and electronic properties.(Zeitschrift für und allgemeine Chemie., 2014) Ağırtaş, Salih; Dede, Emrah; Gümüş, Selçuk; Dündar, Abdurrahman; Okumuş, VeysiA novel phthalonitrile derivative bearing 2-isopropyl-6- methylpyrimidin-4-yloxy substituents at peripheral positions was synthesized by a nucleophilic substitution reaction. Metallophthalocyanines were obtained from the reaction of the novel phthalonitrile with metal Zn, Cu, Co, and Ni salts. The characterization of the compounds was performed using elemental analysis as well as UV/Vis, FT-IR, and 1H-NMR spectroscopy. The aggregation behaviors of phthalocyanine complexes were also investigated. These metallophthalocyanines do not show any aggregation behavior between 10–4–10–6 M concentration range in THF. The antioxidant activities of the synthesized com-pounds were evaluated using three different tests: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, metal chelating activity, and reducing power assays. All the compounds exhibited various antioxidant activities. In addition, antimicrobial activity of the compounds was tested over four gram positive and two gram negative bacteria. Moreover, the ground-state geometries of the complexes were optimized using density functional theory (DFT) methods at B3LYP/6- 31G(d,p) level in order to obtain information about the 3D arrangements and electronic structure.Öğe New water soluble phenoxy phenyl diazenyl benzoic acid substituted phthalocyanine derivatives: Synthesis, antioxidant activities, atypical aggregation behavior and electronic properties.(Dyes and Pigments, 2013) Ağırtaş, Salih; Çelebi, Metin; Gümüş, Selçuk; Özdemir, Sadin; Okumuş, VeysiNovel substituted phthalonitrile derivatives were obtained by the reaction of 2-(4-hydroxyphenylazo) benzoic acid and 4,5-dichloro-1,2-dicyanobenzene, or 4-nitrophthalonitrile. Peripherally phenoxy phenyl diazenyl benzoic acid substituted zinc (II) phthalocyanine complexes, and their sodium salts were synthesized and characterized for the first time. The newly synthesized phthalocyanine complexes show excellent solubility in water. The aggregation investigations carried out in different concentrations indicate that phenoxy phenyl diazenyl benzoic acid-substituted phthalocyanine compounds do not have any aggregation behavior for the concentration range of 7.00 _ 10_5e4.38 _ 10_6 M in DMF. The antioxidant activities of DMF solution of compounds were analyzed through radical scavenging, and chelating ability to Fe2ş cation. Additionally, new compounds did not show any antibacterial activity against some selected bacteria cultures. Moreover, the ground-state geometries of the complexes were optimized using density functional theory (DFT) methods at B3LYP/6-31G(d,p) level in order to obtain information about the 3D geometries and electronic structure.Öğe Novel cobalt (II), zinc (II) phthalocyanines bearing discrete substituents: Synthesis, characterization, aggregation behavior, electrochemical properties and antioxidant activity(Synthesis and Reactivity in Inorganic, Metal-Organic & Nano Metal Chemistry, 2014) Ağırtaş, Salih; Cabir, Beyza; Dündar, Abdurrahman; Okumuş, Veysi; Ceyhan, GökhanA new phthalonitrile derivative bearing 3,4,5-trimethoxybenzyloxy and chloro-substituents at peripheral position was prepared by a nucleophilic displacement reaction. Cyclotetramerization of phthalonitrile derivative in dimethylsulfoxide (DMSO) gave the metallophthalocyanines. Novel Co(II), Zn(II) phthalocyanines (Pcs) were obtained from the reaction 4-[(3,4,5- trimethoxybenzyloxy]-5-chlorophthalonitrile and metal salts. The novel compounds have been characterized by using elemental analysis, UV-Vis, FTIR, 1H-NMR spectral data. The aggregation behaviors of Co(II), Zn(II) Pcs were also investigated. These metallophthalocyanines do not show any aggregation behavior between 1.2 × 10−5 and 4.0 × 10−6Mconcentration range in DMF. The antioxidant activities of Pcs were investigated antioxidant assays such as free radical scavenging ability of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferrous ion chelating ability. Furthermore, the redox properties of the Pcs complexes were investigated by using cyclic voltammetry.Öğe Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent for preconcentrations of Cd2 and Co2 and their determination by ICP-OES(Elsevier B.V., 2012) Özdemir, Sadin; Okumuş, Veysi; Klnç, Ersin; Bilgetekin, Havin; Dündar, Abdurrahman; Ziyadanogullar, BerrinThis article reports a method that is used for the preconcentration and determination of Cd2 and Co2 in vegetables, using Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent. The concentrations of metals were determined by inductively coupled plasma-optical spectrometry (ICP-OES). Critical parameters, such as the pH of the solution, flow rate, the amount of biosorbent, type and volume of eluent, and the sample volume, that affect the solid-phase extraction (SPE) procedure were optimized. The optimum extraction conditions were determined as being a pH of 6.0 for Cd2 and of 5.0 for Co2; a sample flow rate of 2.0 mL min-1; 200.0 mg of biosorbent; and 5.0 mL of 1.0 mol L-1 HCl as eluent. The capacities of the biosorbent for metal uptake were found to be 11.3 and 9.8 mg g-1 for Cd2 and Co2 ions, respectively. Limit of quantitations (LOQs) were found to be 0.67 and 0.82 ng mL-1, respectively, for Cd2 and Co2. The linear working curves were observed to be in the linear range from 1.0 to 50.0 ng mL-1, and possessed high correlation coefficients. The use of the SPE method showed 50.7- and 35.7-fold improvements in the sensitivities of ICP-OES. The developed method was successfully applied to NCS ZC-73014 (a certified reference tea sample). Relative standard deviations (RSD) were lower than 5.0%. The Cd2 and Co2 concentrations in the different parts (leave, root, stem, and fruit) of purslane, onion, rocket, okra, and aubergine were determined after microwave digestion and solid-phase extraction by P. eryngii immobilized on Amberlite XAD-16. © 2012 Elsevier B.V.Öğe Pleurotus eryngii immobilized amberlite XAD-16 as a solid-phase biosorbent for preconcentrations of Cd2+ and Co2+ and their determination by ICP-OES(Talanta, 2012) Özdemir, Sadin; Okumuş, Veysi; Kılınç, Ersin; Bilgetekin, Havin; Dündar, Abdurrahman; Ziyadanoğulları, BerrinThis article reports a method that is used for the preconcentration and determination of Cd and Co in vegetables, using Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent. The concentrations of metals were determined by inductively coupled plasma-optical spectrometry (ICP-OES). Critical parameters, such as the pH of the solution, flow rate, the amount of biosorbent, type and volume of eluent, and the sample volume, that affect the solid-phase extraction (SPE) procedure were optimized. The optimum extraction conditions were determined as being a pH of 6.0 for Cd and of 5.0 for Co; a sample flow rate of 2.0 mL min_1; 200.0 mg of biosorbent; and 5.0 mL of 1.0 mol L_1 HCl as eluent. The capacities of the biosorbent for metal uptake were found to be 11.3 and 9.8 mg g_1 for Cd and Co ions, respectively. Limit of quantitations (LOQs) were found to be 0.67 and 0.82 ng mL_1, respectively, for Cd and Co. The linear working curves were observed to be in the linear range from 1.0 to 50.0 ng mL_1, and possessed high correlation coefficients. The use of the SPE method showed 50.7- and 35.7-fold improvements in the sensitivities of ICP-OES. The developed method was successfully applied to NCS ZC-73014 (a certified reference tea sample). Relative standard deviations (RSD) were lower than 5.0%. The Cdand Co concentrations in the different parts (leave, root, stem, and fruit) of purslane, onion, rocket, okra, and aubergine were determined after microwave digestion and solid-phase extraction by P. eryngii immobilized on Amberlite XAD-16.Öğe Preconcentration of metal ions using microbacteria(Microchimica Acta, 2013) Özdemir, Sadin; Okumuş, Veysi; Dündar, Abdurrahman; Kılınç, ErsinThis review (160 refs). covers the current state of the art of microbacteria-based sorbents for preconcentration of metal ions at trace levels. We highlight advantages and major challenges of the techniques and discuss future perspectives of both batch and column-based methods. Particular attention is paid to the preconcentration of metal ions using resinimmobilized microbacteria for solid phase extractions. We also discuss detection methods including UV–vis spectrophotometry, FAAS, ICP-OES and ICP-MS. Analytical figures of merit are compared, and examples are given for the application to a variety of samples including food, beverages, alloys, water, soil, and geological samples.Öğe Preconcentration of Sn in real water samples by solid phase extraction based on the use of helvella leucopus as a fungal biomass prior to its determination by ICP-OES(Atomic Spectroscopy, 2013) Kılınç, Ersin; Dündar, Abdurrahman; Özdemir, Sadin; Okumuş, VeysiRecently, biosorbents of biological origin such as fungus, algae, and bacteria have found special application as packing material in solid phase extraction (SPE). In this study, an alternative SPE method was developed and validated for the preconcentration of Sn prior to its determination by inductively coupled plasma optical emission spectrometry (ICPOES). Helvella leucopus, a fungal biomass, was used as the biosorbent in the column studies. Experimental parameters, such as Ph and flow rate of the solution, amounts of biosorbent and resin, and volume of the sample solution which affects the analytical results, were investigated. Effects of possible interfering ions on the SPE preconcentration of Sn were investigated. The sensitivity of ICP-OES was improved 47.1 times for Sn. The LOD and LOQ values were 0.06 and 0.21 ng mL-1, respectively. Linearity was obtained in the concentration range of 1.0–30 ng mL-1 for Sn. The loading capacity of Helvella leucopus immobilized Amberlite XAD-4 was 10.4 g g-1. The concentrations of Sn in the water samples from the Tigris River were determined using the developed method and validated by analysis of the certified reference material NWTM-26.3 Fortified Water sample.
